Urban green areas provide multiple environmental services, contributing to high-quality environments in our cities. With the purpose of evaluating the influence of urban green spaces in air quality, noise and thermal comfort, a research was developed throughout the last 4 years in the city of Bragança, Portugal. All these aspects were approached from physical and social perspectives. The physical approach involved several studies at urban and green space scales. Field experiments covered such areas as measurements of air pollutants concentrations (ozone, nitrogen dioxide, volatile organic compounds and PM10), sound pressure levels, meteorological and other parameters related to thermal comfort. The social approach consisted in assessing perceptions of citizens over green spaces and their influence on the environment, alongside with the assessment of their attitudes towards those spaces, by means of specific questionnaires applied to a representative sample of local inhabitants.
Results showed the relevance of the green spaces in contributing to ameliorate air quality, create more pleasant soundscapes and provide better thermal comfort conditions, especially in spring and summer. Relations between benefits of green spaces and their size, their physical and biological diversity, and their location were found. These characteristics were also identified by respondents as key factors in a moment of selecting a green space to pass the time and to enjoy part or all services it can provide. In the opinion of the respondents, those factors are crucial in maximizing many environmental and social functions of urban green spaces.